1. Field of the Invention
The present invention relates to a process for forming color images using plural kinds of color ink including black ink, in a recording system such as a pen recording system and an ink jet recording system.
2. Description of the Prior Art
Lately researches and developments have extensively been carried out concerning color graphic printers and full color digital copying machines using a pen recording system or an ink jet recording system. In the above-mentioned machines, multicolored images are usually formed by using mainly cyan ink, magenta ink, and yellow ink (suitably adding black ink), and overlapping and mixing more than one kind of ink corresponding to necessity. In forming multicolored images using plural kinds of color ink, each dye contained in cyan-, magenta-, or yellow-ink are required to exhibit right absorption spectra as precisely as possible, and to have excellent color reproducibility when adhered to a recording medium such as paper and the like.
Moreover, when a color image is formed by overlapping more than one kind of color ink, each color ink must necessarily be prepared so that the overlapped and synthesized images may reproduce the color tone of the original image with fidelity on the recording medium.
Heretofore efforts have been made from the above point of view to prepare each ink to obtain desired color images by combining these inks based on theoretical calculations. However, it has been extremely difficult to reproduce practically the color on a recording medium as is theoretically predicted.